Voltage controlled oscillators (VCOs) are ubiquitous circuits used in a large variety of electronic devices. For example, the VCO is an essential building block of phase-lock loops (PLLs), which may be found in cellular telephones, data storage devices, fiber optic communication systems and satellite radio receivers.
While VCOs are not generally thought to be “power hungry” pieces of circuitry, the proliferation of hand-held devices, such as cellular phones, has put pressure on the designers of electronic equipment to produce increasingly energy-efficient VCOs. Unfortunately, traditional methods of reducing power consumption in VCOs tend to cause such VCOs to exhibit increased noise, which in turn tends to lower their performance. Accordingly, it should be appreciated that even modest energy savings may degrade a VCO's performance to the detriment of the system incorporating the VCO.